1. Technical Field of the Invention
The present invention relates to a method for correcting the harmonic distortion of a power bridge.
The invention also relates to a compensation system.
The invention particularly, but not exclusively, relates to a method for compensating a harmonic distortion introduced by a power bridge in a class D amplifier and the following description is made with reference to this field of application for simplifying the illustration only.
2. Description of Related Art
As is well known, class D amplifiers currently for sale use an analog or digital modulator of the PWM type for driving a power bridge. The non idealities in the power bridge are responsible for an increase in harmonic distortion that can be measured downstream of this amplifier (for example, in the load).
To overcome this problem, the use of systems comprising a class D amplifier and a feedback path is known. In particular, these systems with feedback measure a signal at the output of the class D amplifier and report this information to the input of the modulator for calculating the error made.
The systems with feedback, however, require specific additional components (such as integrators, comparators, analog-to-digital converters) which increase the cost of the system as a whole.
Systems are also known comprising class D amplifiers in an open loop configuration which include at least one estimation block for estimating and providing the error on a signal at the output of the amplifier. The system then acts on the modulator for compensating in advance of this estimated and provided error.
These open loop systems do not give efficient results in practice as regards the decrease of the distortion introduced by a power bridge of a class D amplifier.
A need accordingly exists for providing a method for compensating a system comprising a class D amplifier, having such structural and functional characteristics as to reduce the harmonic distortion introduced by the power bridge of the amplifier overcoming the limits and drawbacks still affecting the systems realized according to the prior art.